mantyr / goofys

a Filey System for AWS S3 written in Go

Goofys is a Filey-System interface to S3

Overview

Goofys allows you to mount an S3 bucket as a filey system.

It's a Filey System instead of a File System because goofys strives for performance first and POSIX second. Particularly things that are difficult to support on S3 or would translate into more than one round-trip would either fail (random writes) or faked (no per-file permission). Goofys does not have a on disk data cache, and consistency model is close-to-open.

Usage

Pre-built binaries are available here. You may also need to install fuse-utils first.

$ go get github.com/kahing/goofys
$ go install github.com/kahing/goofys
$ cat > ~/.aws/credentials
[default]
aws_access_key_id = AKID1234567890
aws_secret_access_key = MY-SECRET-KEY
$ $GOPATH/bin/goofys <bucket> <mountpoint>

Users can also configure credentials via the AWS CLI or the AWS_ACCESS_KEY and AWS_SECRET_KEY environment variables.

To mount an S3 bucket on startup, make sure the credential is configured for root, and can add this to /etc/fstab:

goofys#bucket   /mnt/mountpoint        fuse    allow_other,--file-mode=0666    0       0

Benchmark

Using --stat-cache-ttl 0 --type-cache-ttl 0 for goofys -ostat_cache_expire=1 for s3fs to simulate cold runs. Detail for the benchmark can be found in bench.sh. Raw data is available as well. Test was run on an EC2 c4.xlarge in us-west-2a connecting to a bucket in us-west-2. Units are seconds.

operation	goofys	s3fs	speedup over s3fs	riofs†	speedup over riofs
Create 100 files	5.31+/-0.35	33.7+/-2.5	6.3+/-0.6x	1.43+/-0.21†	0.27+/-0.04x
Unlink 100 files	3.1+/-0.4*	6.6+/-0.6	2.12+/-0.32x	3.63+/-0.33	1.17+/-0.17x
Create 100 files (parallel)	2.45+/-0.30	29.4+/-1.7*	12.0+/-1.6x	1.25+/-0.16†	0.51+/-0.09x
Unlink 100 files (parallel)	3.10+/-0.35	9.7+/-1.7	3.1+/-0.7x	4.2+/-0.4	1.36+/-0.20x
ls with 1000 files	0.73+/-0.05*	36.8+/-2.5	50.1+/-5.1x	9.9+/-0.5*	13.4+/-1.2x
Write 1GB	11.7+/-1.8*	38.4+/-6.2*	3.3+/-0.7x	117.1+/-3.7	10.0+/-1.6x
Read 1GB	17.1+/-1.1*	22.0+/-6.7*	1.3+/-0.4x	25.2+/-1.0	1.48+/-0.11x
Time to 1st byte	0.036+/-0.013*	1.1+/-0.4	31.0+/-16.8x	0.275+/-0.018*	7.6+/-2.9x

(*) indicates the number of outliers removed

(†) riofs does not wait for HTTP response before returning from release()

License

Copyright (C) 2015 Ka-Hing Cheung

Licensed under the Apache License, Version 2.0

Current Status

List of not yet implemented fuse operations:

• in terms of syscalls
  • readlink
  • chmod/utimes/ftruncate
  • fsync

List of non-POSIX behaviors/limitations:

• only sequential writes supported
• does not support appending to a file yet
• file mode is always 0644 for regular files and 0700 for directories
• directories link count is always 2
• file owner is always the user running goofys
• ctime, atime is always the same as mtime
• cannot rename non-empty directories
• unlink returns success even if file is not present
• can only create files up to 50GB
• no symlink support

References

• Data is stored on Amazon S3
• Amazon SDK for Go
• Other related fuse filesystems
  • s3fs: another popular filesystem for S3
  • gcsfuse: filesystem for Google Cloud Storage. Goofys borrowed some skeleton code from this project.
• S3Proxy is used for go test
• fuse binding, also used by gcsfuse